Metal‐free aerobic oxidative esterification of aromatic aldehydes promoted by potassium fluoride (KF)

We investigated the oxidative esterification of aldehydes with alcohols/phenols to produce a range of esters. In this approach, we conducted the reaction under metal‐free conditions at room temperature. The reactions were promoted by potassium fluoride (KF) as the additive, resulting in the desired product in good to high yields. This procedure was found to be effective for the production of aryl esters, which are challenging in most of the available reports. It is vital for this procedure not to exclude air as the source of oxygen.     

Bactericidal effects of Ag nanoparticles immobilized on surface of SiO2 thin film with high concentration

Bactericidal activity of high concentration Ag nanoparticles immobilized on surface of an aqueous sol–gel silica thin film was investigated against Escherichia coli and Staphylococcus aureus bacteria. Size of the surface nanoparticles was estimated in the range of 35–80 nm by using atomic force microscopy. Due to accumulation of the silver nanoparticles at near the surface (at depth of 6 nm and about 40 times greater than the silver concentration in the sol), the synthesized Ag–SiO₂ thin film (with area of 10 mm²) presented strong antibacterial activities against E. coli and S. aureus bacteria with relative rate of reduction of the viable bacteria of 1.05 and 0.73 h⁻¹ for initial concentration of about 10⁵ cfu/ml, respectively. In addition, the dominant mechanism of silver release in long times was determined based on water diffusion in surface pores of the silica film, unlike the usual diffusion of water on the surface of silver-based bulk materials. Therefore, the Ag nanoparticles embedded near the surface of the SiO₂ thin film can be utilized in various antibacterial applications with a strong and long life activity.     

Developments in analytical fourier-transform mass spectrometry

Development of a differentially-pumped, dual-cell geometry, coupled with the evolution of pulsed-laser desorption and Cs⁺-secondary-ion mass spectrometric (s.i.m.s.) desorption methods, has improved the analytical utility of Fourier-transform mass spectrometry (F.t.m.s.). A survey of applications and performances obtained in our laboratories is presented. Among the topics covered are ultra-high-resolution electron-impact and chemical-ionization mass spectra, gas chromatography/F.t.m.s. performance, pulsed Cs⁺-s.i.m.s./F.t.m.s. with cooled liquid matrices and solid samples, laser desorption/F.t.m.s. and accurate mass measurements taken under each of these modes of operation.     

Copper-catalyzed synthesis of α-ketothioamides from ketones

In this paper, the conversion of acetophenone to α-ketothioamide was reported in the presence of CuI as the catalyst and S₈/DMF as the coupling partners. The presence of both KF and NaOH was found to be necessary to achieve the high yield of the product. Propiophenone and butyrophenone also reacted in the presence of phenylboronic acid as an additive. Willgerodt-Kindler products were not observed in these reactions.     

Silica sulfuric acid as an efficient catalyst for the Friedländer quinoline synthesis from simple ketones and ortho-aminoaryl ketones under microwave irradiation

The synthesis of quinoline derivatives via Friedländer method from ortho-aminoaryl ketones in the presence of a catalytic amount of silica sulfuric acid (SSA) under solvent-free condition and microwave irradiation was described. A good range of simple ketones such as cyclohexanone and deoxybenzoin were used.     

Electrochemical Synthesis of 2-(2-Chlorophenyl)-2-[(3,4- dihydroxyphenyl)(methyl)amino]cyclohexanone

Russian Journal of Electrochemistry - Electrochemical oxidation of catechol has been studied in the presence of ketamine as a drug in phosphate buffer solution mixed with ethanol using voltammetric...